https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121559
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2025-08-18
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Keywords| |missed-optimization
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Yeah, the lattice cannot express this. Copy-propagation support was added
because it was a cheap thing to do, it does not behave exactly like the
copy propagatation in the copyprop pass. IIRC I tried unifying both passes
at some point, but this didn't work out (I don't remember the actual issue).
Note forwprop also does copy and constant propagation, so it should not need
a ccp/copyprop pass before it.
